Wind is one of the most important renewable energy technologies. Wind turbines (also referred to as a wind driven power plants or wind energy converters) are more and more arranged in large-scale offshore wind parks. There are many technical challenges relating to these offshore wind parks, as for example the assembly of parts and the transport, the erection of the wind turbine in the sea and the maintenance of the wind driven power plants.
WO 2009/132671 A2 discloses a wind energy installation with a nacelle with a paneling. The paneling is configured with a hatch opening that is arranged in the paneling covering surface. The hatch opening is sufficiently large in dimension to allow components to be removed or introduced in an upward direction from the top into the nacelle over the whole area of the drive train of the wind energy installation. The hatch opening can be opened and closed by a hatch cover that is configured to be slid as a whole along the top of the nacelle. Furthermore, a helicopter hoisting platform is provided on top of the nacelle and the cover is configured to slide below the hoisting platform in order to open the hatch. It is an object of the invention to provide a wind power installation for a nacelle of a wind driven power plant with a helicopter hoisting platform allowing the wind power installation or its parts to be easily transported, assembled and mounted, in particular for offshore wind parks. The helicopter hoisting platform generally serves to hoist persons down to the platform on the nacelle. The purpose may be all kinds of inspection or data collection from sensors of the nacelle.